How to get file in notes (csv) using javascript, open it and allocate the lines of it in variables?

I'm trying to upload a CSV file using IBM Notes.

I have the function that uploads the file working.

The problem is to open it using javascript inside Notes and read the file in CSV.

I tried to use the FOpen command available in JavaScript, but the function that stores the file on the server in JavaScript does not have access methods included.

How to return the contents of the FileUpload file?